Author Topic: So, i dynoed my bike today (Read 2836 times)

wookie · « **on:** August 28, 2010, 03:06:41 PM »

The Results

My max power was a decent 74.6 but a solid 71. He figures getting the carbs set up right could net me @80. The top end works well we just need to tune the mid range.

The red run was a roll in, the blue was thru the gears and the green was a comparison run by another highly modified 750.

Specs. 836/Dynoman 295 cam/ pods/ 4 into 1/ Dyna s/ CR 29's set at 125 mains, clip at third from top, 240 air, gearing 17/46

Jerry Rxman Griffin aka MuthaF'er · « **Reply #1 on:** August 28, 2010, 03:41:46 PM »

The dyno chart looks as good as your bike. Hope to see a comparison once the jetting is squared away. What's your elevation?

tweakin · « **Reply #2 on:** August 28, 2010, 04:20:28 PM »

Nice Jamie, really makes me upset about missing the ride over to Winthrop tomorrow. I got my flight changed so I am leaving out early Monday am rather than Sunday but it would be impossible to do the ride and be ready to go Monday am.

Bike looks great and so does the dyno.

wildcatmahone · « **Reply #3 on:** August 28, 2010, 05:05:34 PM »

Nice, are you happy with the results?

Alan F. · « **Reply #4 on:** August 28, 2010, 07:02:06 PM »

I'd have loved to hear that run.

MCRider · « **Reply #5 on:** August 28, 2010, 08:39:18 PM »

Do you have a ported head?

Thansk for the Dyno runs, I like to see this typpe of stuff.

wookie · « **Reply #6 on:** August 29, 2010, 12:05:54 AM »

Thanks Jerry, I am at sea level. Give or take a few feet. Have to order some jetting stuff from sudco.

Thanks Tige,
Labour Day.... Book it.

Wildcatmahone,
There is room for improvement in everything. I want more, and will get it.

Alan,

I will post video next time. It happened all so fast and was kind of scary. He asked me what i wanted him to rev it too. 9500 i guess, i said. It's just not the same standing beside a bike revving that high;)

Mcrider,
Head is stock. Valves set to .005 and .008 respectively to webcam specs.

Alan F. · « **Reply #7 on:** August 29, 2010, 07:03:01 PM »

I spent a few months wrenching at a dyno mfg. in New Hampshire years ago, wild stuff for sure.

wookie · « **Reply #8 on:** August 29, 2010, 07:18:33 PM »

On but off topic,

There is surely something about a dyno which makes the hair on the back of my neck stand up. Years ago i took a 91 VW Gti and dropped a Corrado VR6 into it, Big cams, throttle body, chip, 60mm supersprint exhaust. This thing sounded F1-esque going thru tunnels.
Anyhow, one day we took it to a dyno and strapped it on. Watching your car rev to 7500 and spit fire at eye level was one of the coolest things i have experienced. It made 171bhp Quarter mile in 14.53@98mph.

I miss that one.

Retro Rocket · « **Reply #9 on:** August 29, 2010, 07:23:33 PM »

Quote from: cbcafe on August 29, 2010, 07:18:33 PM

On but off topic,

There is surely something about a dyno which makes the hair on the back of my neck stand up. Years ago i took a 91 VW Gti and dropped a Corrado VR6 into it, Big cams, throttle body, chip, 60mm supersprint exhaust. This thing sounded F1-esque going thru tunnels.
Anyhow, one day we took it to a dyno and strapped it on. Watching your car rev to 7500 and spit fire at eye level was one of the coolest things i have experienced. It made 171bhp Quarter mile in 14.53@98mph.

I miss that one.

Hmmmmm, i'd have thought it would have been a bit quicker than that.....all that work and only 171HP..??

Do yourself a favour and port the head on your bike, there is more horse power locked up there than in any other part of the bike. Then get your self some serious valve springs and some titanium retainers and better quality valves........

Mick

Alan F. · « **Reply #10 on:** August 29, 2010, 07:39:11 PM »

Yeah, cars suck.

wookie · « **Reply #11 on:** August 29, 2010, 09:32:31 PM »

Quote from: retro rocket on August 29, 2010, 07:23:33 PM

Quote from: cbcafe on August 29, 2010, 07:18:33 PM
On but off topic,

There is surely something about a dyno which makes the hair on the back of my neck stand up. Years ago i took a 91 VW Gti and dropped a Corrado VR6 into it, Big cams, throttle body, chip, 60mm supersprint exhaust. This thing sounded F1-esque going thru tunnels.
Anyhow, one day we took it to a dyno and strapped it on. Watching your car rev to 7500 and spit fire at eye level was one of the coolest things i have experienced. It made 171bhp Quarter mile in 14.53@98mph.

I miss that one.

Hmmmmm, i'd have thought it would have been a bit quicker than that.....all that work and only 171HP..??

Do yourself a favour and port the head on your bike, there is more horse power locked up there than in any other part of the bike. Then get your self some serious valve springs and some titanium retainers and better quality valves........

Mick

171 at the wheels still propelled me to 150mph. It did weigh 2400lbs

As for my head, i plan on reworking it down the road.

Logan80 · « **Reply #12 on:** August 30, 2010, 12:07:12 AM »

Quote from: cbcafe on August 29, 2010, 07:18:33 PM

On but off topic,

There is surely something about a dyno which makes the hair on the back of my neck stand up. Years ago i took a 91 VW Gti and dropped a Corrado VR6 into it, Big cams, throttle body, chip, 60mm supersprint exhaust. This thing sounded F1-esque going thru tunnels.
Anyhow, one day we took it to a dyno and strapped it on. Watching your car rev to 7500 and spit fire at eye level was one of the coolest things i have experienced. It made 171bhp Quarter mile in 14.53@98mph.

I miss that one.

My other project is a 1993 Corrado VR6 that's in the middle of getting cams, chip, header, bigger injectors, port/polish, possible big valve head, and to top it all off a Vortech Blower! It's gonna be fun...

MRieck · « **Reply #13 on:** August 30, 2010, 12:34:34 AM »

Quote from: Alan F. on August 29, 2010, 07:39:11 PM

Yeah, cars suck.

Gospel

Retro Rocket · « **Reply #14 on:** August 30, 2010, 12:38:11 AM »

Quote from: MRieck on August 30, 2010, 12:34:34 AM

Quote from: Alan F. on August 29, 2010, 07:39:11 PM
Yeah, cars suck.
Gospel

Trust Mike to turn up when we start talking head........that didn't come out all that well, did it..?......

Mick

nippon · « **Reply #15 on:** August 30, 2010, 02:04:28 AM »

@cbcafe,....nice chart.
but with CR29 carbs i expected a little bit more.
Reason, I run stock carbs with 836ccm and head work and get 74.5 hp at the wheel. It would be nice to see a new dynorun of your bike with the CR29s when you set 'em up.

nippon

Retro Rocket · « **Reply #16 on:** August 30, 2010, 02:56:14 AM »

Quote from: nippon on August 30, 2010, 02:04:28 AM

@cbcafe,....nice chart.
but with CR29 carbs i expected a little bit more.
Reason, I run stock carbs with 836ccm and head work and get 74.5 hp at the wheel. It would be nice to see a new dynorun of your bike with the CR29s when you set 'em up.

nippon

Without head work i doubt he will get much better results....

Mick

voxonda · « **Reply #17 on:** August 30, 2010, 03:29:29 AM »

Think you are right, Mick. Though there is a small profit the big gain is after headwork. The oem porting is 'poor'. But think Honda learned through the years. Just put some CR 33 on a standard CB900 Bol d'or DOHC, that gives a tremendous boost. (with a good pipe that is)

Rob

nippon · « **Reply #18 on:** August 30, 2010, 03:55:14 AM »

Did not recognize that he did not make some head work.

nippon

supersports400 · « **Reply #19 on:** August 30, 2010, 05:41:47 AM »

Hi,

Nice work, I like to see more of this.
I see that your chain is a bit worn, lot's of fluctuations on top of the curve.

I don't see a torque curve and no mixture analyzer curves, do you have them ?
You need those three to say something about the possibility's of the engine.

The torque curve can be determined from the power curve, and mixture curve comes from a gas analyzer.
It's more informative to put the rpm on the horizontal axis instead of the speed.

It seems that there is a real big issue in the transition from the lower rpm's to the higher rpm's, a torque curve and a rpm horizontal axis would reveal that, and the reason would be revealed by the mixture curve.

Is there another reason for the issue's in the blue line while accelerating ? (clutch, bad shifting)
From this curve, at least, I cannot conclude that other carbs are necessary or that the head needs a flowed.

It's not my intension to be offensive, but if you feel that way, please ignore my reaction,

Jensen

wookie · « **Reply #20 on:** August 30, 2010, 05:19:22 PM »

Let's keep in mind here that the intention of me putting the bike on the dyno was to get a baseline reading for the work that i have done so far. The shop is closing Sept 4th. so i had to get it done.
I have a 'seat of the pants' dyno but it doesn't give me any numbers to work with.

Jensen,

I will take your comments with a grain of salt here. There is a whopping 600 miles on this bike so far so i doubt the chain is worn. All the info i have i posted, no gas analyzer readings but i do know it is running rich.

Why would i put other carbs on it? I already have the cat's ass.

Retro Rocket · « **Reply #21 on:** August 30, 2010, 05:28:21 PM »

The standard chains stretch pretty easily and with a bigger bore this will happen faster,something is causing those fluctuations at high revs, could even be the standard valve train. As far as carbs go the CR's are the cheapest performance carbs, the mikuni's are the ants pants and there are a few fuel injected bikes on here as well. Forum member Nippon has heavy duty primary chains for these bikes with far less stretch than the stock chains, i have a set in my 1000cc build...I am glad you posted pics of the bike as i was considering using a boldor tank on a "F" framed bike i have....looks great..

Mick

wookie · « **Reply #22 on:** August 30, 2010, 06:35:06 PM »

Thanks Mick,, seems i have some learning to do. To be honest, i don't really feel like tearing down my motor to find a fluctuation if it isn't detrimental yet. I am going to continue to tune the carbs and will consider other work when the snow falls.

All things considered, these results are acceptable are they not?

I'm not expecting a superbike here, could have bought one but i prefer built over bought.

HondaMan · « **Reply #23 on:** August 30, 2010, 06:42:05 PM »

Nice work, cb750cafe!

Pulling out that kind of HP from a freshly-rebuilt 750 shows you did a bunch of things right. After break-in, maybe that head work, a quench band to fit up to the 836 bores: you'll cross that 80 HP line.

Good job!

Retro Rocket · « **Reply #24 on:** August 30, 2010, 07:00:02 PM »

Quote from: HondaMan on August 30, 2010, 06:42:05 PM

Nice work, cb750cafe!

Pulling out that kind of HP from a freshly-rebuilt 750 shows you did a bunch of things right. After break-in, maybe that head work, a quench band to fit up to the 836 bores: you'll cross that 80 HP line.

Good job!

+1, those are good numbers for a bike with a stock head......

Mick

wookie · « **Reply #25 on:** August 30, 2010, 08:14:02 PM »

thanks guys.

Mick, just checked on Mikunis.... Too rich for my blood;)

Retro Rocket · « **Reply #26 on:** August 30, 2010, 11:39:22 PM »

Quote from: cbcafe on August 30, 2010, 08:14:02 PM

thanks guys.

Mick, just checked on Mikunis.... Too rich for my blood;)

Yep, they are expensive but they are super nice and are supposed to be the best carb for our bikes........Time toput the lottery on....

Actually i am thinking about getting a set for the bike i am going to inject, just forthe run in period them put them on my 2nd bike....

Mick

supersports400 · « **Reply #27 on:** August 31, 2010, 04:08:44 AM »

Hi,

Like I said, don't feel offensive here, it was just an observation from the results on paper you provided.
Maybe primary chain slack, secondary chain slack, maybe something different, but it's there, it's measured and documented.

How do you know it running rich ?, and where precisely is it running rich ?
Why the dip in the midrange ?, what is the torque curve saying about that ?

In general, a simple dyno run, without the torque curve, and without a mixture curve says nothing about the potentials of the engine and should be seen only as an ”as is” curve, and probably that was your intention.

Jensen

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Author Topic: So, i dynoed my bike today (Read 2836 times)